This invention relates to detergent compositions containing cellulose-based soil release ethers. More particularly, the compositions herein are formulated from optimal, narrow "cuts" of alkyl sulfate surfactants which do not substantially interfere with the soil release performance of the cellulose ethers.
As noted hereinafter, much effort has been expended in designing various compounds which are capable of conferring soil release properties to fabrics during a home laundering operation. The extensive work in this area has, in the main, been directed toward using various polymers as detergent additives with the goal of depositing such polymers onto cotton, polyester and polyester/cotton fabrics from an aqueous laundry bath to secure a soil release benefit in subsequent launderings.
For the most part, the literature relating to soil release polymers indicates that efforts to improve the efficacy of detergent compositions containing such materials as additives has focused on the nature of the polymers themselves, and a great variety of such polymers have been prepared and tested.
The continuing search for detergent compositions containing truly effective soil release additives reflects the recognition that many such materials are not particularly useful in this regard, other than at high concentrations. Of course, the use of high concentrations of any additive in detergent compositions is an economic waste if lower amounts would suffice. Moreover, such additives are preferably degraded before being released into water supplies. While many of the prior art soil release materials are entirely acceptable from a toxicological standpoint, their presence in sewage effluents in high concentrations results in an increased biological oxygen demand, with a decrease in water quality. Accordingly, it would be useful to provide detergent compositions containing small, yet effective, amounts of soil release additives.
The most attractive types of soil release polymers are those based on cellulose as a raw material. The cellulose ethers are one such type of polymer. The cellulose ethers are simple to prepare, biodegradable, and are quite acceptable from a toxicological standpoint. Indeed, many such materials are known for use as food additives.
Various cellulose ether soil release polymers are known in the art, and many such materials have been suggested for use both in laundry baths in combination with surfactants and in rinse baths in the absence of surfactants. Clearly, from the standpoint of ease-to-use, it is more convenient to apply the soil release polymers to fabrics in conjunction with a laundering operation.
It has now been discovered that, contrary to the teachings of the prior art, the selection of surfactant for use in combination with cellulose ethers has a substantial effect on their soil release properties. Many detersive surfactants interact with the cellulosics and substantially decrease their efficacy as soil release agents. Accordingly, the formulators of detergent compositions containing such materials have been constrained either to accept a sub-optimal level of performance, or to use unduly high concentrations of the cellulose ether polymers in detergent compositions to achieve good soil release performance.
It has further been discovered that certain alkyl sulfate surfactants are particularly useful for preparing detergent compositions which impart superior soil release properties to fabrics in the presence of but small quantities of cellulose ether soil release agents. It is especially advantageous that the alkyl sulfates of the type disclosed herein are useful in combination with cellulosics, inasmuch as this general type of surfactant is well-accepted by consumers.
Finally, it has now been discovered that certain fabric finishes, especially those used on polyester/cotton fabrics, have a substantial effect on the ability of cellulose ethers to provide optimal soil release performance benefits. The soil release ethers used in combination with the preferred surfactants herein can be selected from a wide range of cellulosics if unfinished polyester/cotton is being laundered. However, if durablepress finished polyesters, or mixed loads, are being laundered, it is more preferred to select certain cellulosics which are more robust, i.e., those which perform well on both polyesters and finished and unfinished polyester/cotton blends. The basis for selecting such preferred soil release ethers is disclosed hereinafter.
It is an object of the present invention to provide detergent compositions containing soil release additives.
It is another object of this invention to provide detergent compositions which exhibit optimal soil release performance with minimal concentrations of cellulose ether soil release additives.
These and other objects are obtained herein as will be seen from the following disclosure.